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691.
A high-resolution downward surface solar radiation (DSSR) dataset has been produced using geostationary meteorological satellite
measurements. Its validation with in situ observations shows that the daily satellite DSSRs are highly accurate. Comparing
the satellite DSSRs with reanalysis DSSR datasets, the former has higher probability density in a low value range, and lower
density in a high value range. Overestimations of the reanalysis DSSR are significant in the low range. Correlations between
the reanalysis DSSRs and the satellite DSSR are relatively low in the tropics. It is suggested that the satellite DSSRs have
good potential to capture cloud behavior in the tropics. 相似文献
692.
Hidetaka Takeoka Yoshio Tanaka Yuichi Ohno Yukiharu Hisaki Akitsugu Nadai Hiroshi Kuroiwa 《Journal of Oceanography》1995,51(6):699-711
Observations of sea surface currents by HF radar were carried out in the Bungo Channel in summer 1992. The current ellipses of M2 constituent obtained by the observational results agree quite well with those obtained by the ADCP observations, showing that the accuracy of the HF radar measurements is of the same level as ADCP. The results revealed the current structures and their change with the Kyucho in detail. The Kyucho is influenced by the complicated coastal geometry and does not propagate straightly into the Bungo Channel. It propagates further inward after charging the coastal bays with warm water. The current directions change largely, since the currents turn around the stagnant region in the bay filled with the warm water. The northward intrusion begins to be weakened in the southern part of the channel, while it still persists in the northern part. The northward current speeds of the observed Kyucho are about 50 cm/s and sometimes attain 60 to 70 cm/s. 相似文献
693.
Masayuki Takahashi Toshisuke Nakai Takashi Ishimaru Hiroshi Hasumoto Yoshihiko Fujita 《Journal of Oceanography》1985,41(2):73-80
Continuous distribution of the subsurface chlorophyll maximum (SCM) was confirmed in the Kuroshio and neighbouring areas in observations at 15 to 40 km intervals. Chlorophyll amounts occurring in and immediately around the SCM constituted 60 to 80% of the total chlorophyll in the water column above the 1% light level. The SCM zone received 1 to 10% of the surface irradiance at its center and contained sufficient macronutrients to support approximately one doubling of the existing phytoplankton biomass at most stations. There were several stations where there were higher nutrient concentrations that would support more than one doubling of the existing biomass around the SCM zone, and this was interpreted as resulting from uplift of the SCM zone due to upwelling. 相似文献
694.
Using the data from a wind-tunnel experiment, bispectra of orbital-motions of wind-waves and of turbulence are calculated, and nonlinear interaction of wind-waves with turbulence in water are discussed. The wind-waves or the orbital motions of them, at first, produce the turbulence coherent with themselves, and then this coherent turbulence changes to the turbulence noncoherent with wind-waves. Nonlinearity of the velocity fluctuations in the surface layer in water under wind-waves is almost due to the nonlinear energy transfer from the orbital motions of wind-waves to the coherent turbulence. The vertical variations of the power spectra and of the normalized bispectra suggest that the wind driven currents near the surface play an important role in the process from orbital motion of wind-waves to noncoherent turbulence. 相似文献
695.
For the study of the ocean south of Japan, the HIGHER spatial resolution Sea surface temperature (HIGHERS) data have been produced from the AVHRR/NOAA data. The grid size is 0.075 degree and is much smaller than that of the usual sea surface temperature (SST) analysis field, which is gridded at most in 1 degree. In order to calculate accurate SST, the split-window Multi-Channel SST method is applied to cloudless pixels, which are detected with a cloud detection algorithm. The accuracy of the HIGHERS data is checked in comparison with the in-situ observation data. 相似文献
696.
Motohiko Kashima Shiro Imawaki Shin-Ichiro Umatani Hiroshi Uchida Yuji Hashibe Hiroshi Ichikawa Masao Fukasawa 《Journal of Oceanography》2003,59(3):291-301
Theoretically, the geostrophic approximation holds for the low-frequency flow field, but no detailed examination has been
done on how well the estimated geostrophic velocity corresponds with the observed velocity. Intensive surveys were carried
out during 1993–1995 in the Kuroshio and its recirculation regions south of Shikoku, Japan, including repeated hydrographic
surveys and direct current measurements at nominal depths of 700, 1500 and 3000 m. For these depth intervals, vertical differences
of estimated geostrophic velocity are compared with those of observed velocity. For the intermediate layer (between 700 and
1500 m depths), the slope of the regression line is 0.99, correlation coefficient is 0.98, and the root-mean-square of difference
from geostrophic balance is 2.8 cm/s which is close to the estimated error of 2.1 cm/s. For the deep layer (between 1500 and
3000 m depths), the corresponding values are 0.82, 0.93, 1.2 cm/s and 2.0 cm/s, respectively. The results indicate that the
estimated geostrophic velocity compares well with the observed velocity in these regions.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
697.
Direct measurements of mid-depth circulation in the Shikoku basin by tracking SOFAR floats 总被引:1,自引:0,他引:1
Keisuke Taira Shoji Kitagawa Katsuto Uehara Hiroshi Ichikawa Hiroyuki Hachiya Toshihiko Teramoto 《Journal of Oceanography》1990,46(6):296-306
Mid-depth circulation of the Shikoku Basin was measured by tracking four SOFAR floats drifting at the 1,500 m layer. Two floats were released on 17 April 1988 at 30°N, 135°59E and tracked for 433 days. Another two were released on 3 November 1988 at 29°52N and 133°25E, and tracked for 234 days. Two floats flowed clockwise around the Shikoku Warm Water Mass with a diameter of 400 km centered at 31°N and 136°E and a mean drift speed of 4.5 cm sec–1. One of the floats showed about ten counterclockwise rotations with a period of about 8 days and a maximum speed of 80 cm sec–1 in the sea area west to the Izu Ridge. In the east to Kyushu, a southward flow was observed under the northward flowing Kuroshio. The southward flow of 4 cm sec–1 drift speed was considered to be a part of the counterclockwise circulation at deep layers along the perimeter of the Shikoku Basin. One float remained for 234 days in a limited area of 100 km by 150 km in the western part of the basin. 相似文献
698.
Dissolved Organic Matter in Oceanic Waters 总被引:13,自引:0,他引:13
The amount of information on oceanic dissolved organic matter (DOM) has increased dramatically in the last decade thanks to
the advances in chemical characterization. This information has supported the development of some novel and important ideas
for DOM dynamics in the ocean. Consequently, we have a better understanding of the importance of DOM in oceanic biogeochemical
cycles. Here we review studies published mainly during 1995–2001, synthesize them and discuss unsolved problems and future
challenges. The measurement, distribution and turnover of dissolved organic carbon (DOC) are presented as the bulk dynamics
of the oceanic DOM. The size spectrum, elemental composition, and chemical compositions at molecular and functional group
levels are described. The mechanisms proposed for the survival of biomolecules in DOM are discussed.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
699.
太平洋西北海域海水中钇与稀土元素的地球化学 总被引:1,自引:0,他引:1
海水样品是在东京大学海洋研究所科学考察船(淡青丸KT)93-14次航海期间,于1993年9月12日在日本伊豆-小笠原海沟海域(29°05′N,142°51′E,水深9500m)采集的。采用化学萃取-反萃取分离法并结合等离子质谱仪,对样品进行分析研究。结果表明,海水中重稀土相对于轻稀土富集,相对于重稀土和轻稀土来说,中稀土有一定程度的亏损。钇浓度从海水表面随深度的增加而逐渐增加,与稀土元素一样在海水断面上呈营养盐型分布。同时还发现Ho是稀土中与Y相关性最好的元素,并指出Ho/Y的浓度比同样可以用来示踪海洋中水团的移动。 相似文献
700.